# coding=utf-8
from datetime import timedelta, date

def time_create(day_num):
    yesterday_date = (date.today() + timedelta(days = -day_num)).strftime("%Y-%m-%d")
    today = date.today().strftime("%Y-%m-%d")
    return yesterday_date, today


if __name__ == '__main__':
    a, b = time_create(6)
    print(a, b)
    print(type(a))